Add AgentKit walkthrough cookbook (#2197)

Author: nikhils-oai

authors.yaml

@@ -528,3 +528,7 @@ charlie-openai:
   website: "https://wee.ms"
   avatar: "https://avatars.githubusercontent.com/u/181146176?v=4"
 
+nikhils-oai:
+  name: "Nikhil Srivastava"
+  website: "https://www.linkedin.com/in/nsrivast/"
+  avatar: "https://avatars.githubusercontent.com/u/231350150"